Toss the cubed sourdough with 1 tablespoon extra virgin olive oil. Season with a pinch of kosher salt and black pepper.
Arrange the cubes on a baking sheet and transfer to the oven for 10 to 12 minutes until browned. Remove from the oven and set aside.
Make the dressing:
Combine 2 tablespoons lemon juice, 1 teaspoon Dijon mustard, 1 tablespoon honey, 3 tablespoons extra virgin olive oil, and 2 teaspoons poppy seeds in a bowl. Whisk until completely smooth and emulsified. Taste and season with salt and pepper.
Prepare the salad:
Gather the arugula, sliced cucumber, and sliced plumcots in a large bowl. Pour the poppy seed dressing over the salad. Add the toasted sourdough bread cubes and toss to combine.
To serve:
Spoon the salad onto plates and serve with the remaining poppy seed dressing on the side. Enjoy!